Automatic stoker



Oct. s, 1931. F. w. vooz Lamme AUTOMATIC STOKER Filed May 2, 1927 4 Sheets-Sheet l jizz/@Idar j/eflelk, ya@

Oct. 6, 193i. F. w. voDOz AUTOMATIC sToxER Filed May 2, 1927 4 Sheets--Sheel 2 Oct. 6, 1931. F. w. voDoz AUTOMATIC sToxER Filed May 2,- 1927.

4 Sheets-Sheet 3 Oct. 6, 1931. F. w. lvoDoz 1,826,106

AUTOMATIC STOKER Filed May 2, 1927' 4 Sheets-Sheet 4 Milford l'cdefz'o W Q5 www 5 trolling means therefor.

Patented Oct. 6, 1931 FREDERICK W. VODOZ, F WILMETTE, ILLINQIS AUTOMATIC STOKER Application filed May 2,

This invention relates to improvements in automatic stoking devices for furnaces and has for its principal object to provide for an improved form of Stoker and automatic con- More specifically, my invention contemplates the provision of a stoker, automatically responsive to the Weight of the unburned coal and ash carried on the grate bars, the

arrangement being such that when a predetermined amount of fuel is consumed in the furnace and the total weight of the furnace charge carried by the grate drops below a predetermined value, the stoking system operates automatically to shake down the ash,

break up the clinkers, spread the surface coal and to recharge the furnace with new coal in predetermined amounts sufficient to restore the furnace charge to a predetermined Weight. A further object of the invention is to provide, in conjunction with the stoking apparatus, an improved ash removing system whereby the entire operation of charging the furnace and removing the ashes will be automatic and independent of the draft control devices, which may be either manual-y ly or thermostatically operatedto cause the fire to burn with varying degree of intensity so as to give more or less heat as desired.

The invention may best be understood by referring to the accompanying drawings, in which Figure 1 is a view in part elevation of a furnace of the ordinary household type to which my invention has been applied, with parts broken away to show certain details of the operating mechanism.

Figure 2 is a vieW somewhat similar-to Figure' 1, but showing the mechanism in vertical section taken on a line passing through the axis of the main operating and charging shaft.

Figure 3 is an end view of a stoking apparatus, taken on line 3 3 of Figure 1.

Figure 4 is a detail view of the charging carriage taken on line 4 4 of Figure 2.

Figure 5 is another sectional detail view of the charging carriage taken on line 5 5 of Figure 2.

1927. Serial N0. 188,228.

Figure 6 is a detail sectional view of the grate bars taken on line 6 6 of Figure 1.

Figure 7 is a fragmentary plan view of the stoking apparatus with the storage hopper and other parts removed to show details of the charging carriage and spreader carried thereby, and

Figure 8 is a detail View of the main switch controlling mechanism showing in dotted lines the position of the parts when said switch is initially closed to start the forward movement of the charging carriage.

Figure 9 is a diagrammatic view of the actuating mechanism showing the parts in position when the carriage has partially completed its forward feeding movement.

Figure 10 is a'view showing the carriage in its extreme forward position, and the motor reversing switch actuated to cause the carriage to be retracted.

Figure 11 is a view showing the carriage in full y retracted position,` but with the grate .still not fully loaded, in which case the main motor switch remains closed, and the reverse switch is actuated to move the carriage inwardly with a new load.

Figure 12 is a view similar to Fig. 11, but in which the grate has been fully loaded, and

the parts are in position to cause the main motor switch to open, and thereby discontinue further charging of fuel.

Figure 13 is a diagrammatic vie-w of the electric motor control circuit, including the main and reversing switches.

Referring now to details of the device illustrated in the drawings and embodying one form in which my invention may be utilized, 10 indicates a hot-air furnace of the ordinary household type, having an outlet fiue 1l and an inlet draft opening 12 conimunicating with a fire/pot 13 in the usual manner. It will, of course. be understood that this specific type of furnace is. utilized merely as a means of illustration of my invention, but that my improved stoking device can. with slight modiication. be utilized in connection with a wide variety of coal-burning furnaces utilized not only7 for heating houses, but in steam generating plants and the like.

,Tn carrying out my invention, I provide a grate 15 which, in the form shown, is substantially circular so as to conform with the shape of fire box 13. Said grate is mounted for floating movement relative to the fixed portions of the furnace and fire boX, and is suitably counterbalanced so as to be responsive to changes in weight of fuel thereon. In the form herein illustrated, said grate is supported on a eounterbalancing lever system although other counterbalancing devices similar to those used in scales of various types, may also be employed. As shown herein, the counterbalancing system includes a lever 16 integral with said grate, and extending in a horizontal direction through one wall of the furnace and pivotally connected on pivot pin 17 to a suitable support 18 on the exterior of the furnace. The counterbalancing system also includes a compression spring 2O interposed between the free end of the'lever 16 and a fixed overhead support 21 which herein forms the bottom of the charging carriage, as will hereinafter more fully appear. Means for adjusting the tension on spring 20 is pro-y vided, herein consisting of a bolt 23 threaded in the lever 16 and upon which the lower end of spring 20 is seated. Further adjustment of the relative position of the lever system and counterbalancing tension on the spring 20 may be afforded by mounting the pivot pin 17 of said lever on a threaded member 24 so that it can be adjusted vertically in support 18.

The surface of grate 15 is provided with ai j plurality of apertures 26, 26, and in some of these apertures is mounted a plurality of rocking members 27, 27 pivoted on horizontally disposed bars 28, 28 in said grate and with their upper surfaces normally disposed substantially flush with the upper surface of said grate, as is best shown in Figures 1 and 6. These rocking members have arcuate outer margins so as to permit them to rock upwardly on their pivot pins so that the upper surfaces thereof project above the upper surface of grate 15, for the purpose of breaking up any clinkers which are formed adjacent the grate and also to agitate the ashes adjacent the grate and thus effectively shake down the fire. Rocking movement of the members 27, 27 is preferably limited by stops 30, 30 which engage the under surface of the grate. Each of these rocking members 27 is pivotally connected to a rearwardly extending bar 31, the nearest row of rocking members being directly connected to said bar, while the more remote rows of rocking members are connected to said-bar and to each other by links 32, 32. The rear end of the bar 31 is connected to a lever 33 normally arranged in substantially upright position and pivoted at 34 to one side of the coal hopper 35. Means for actuating the lever 33 and grate members 27, 27 herein comprises a spring 36, in cooperation with movement of the stoking mechanism, as will hereinafter appear.

The outer end of the grate supporting lever 16 is provided with a pin 37 which moves in slotted end 38 of link 39. Said link is pivotally connected at 40 with a lever 4l which is in turn pivoted on pin 42 and projects inwardly toward the furnace and is yieldably held in raised position by a spring 43 connected to the side of the hopper 35. 'l`l1e l'ever 41 is provided with a detent 45 which is normally adapted to engage a pin 46 extending inwardly from lever 33, as best shown in Figures 1, 5 and 7.

A rod 47 is connected to the end of lever 4l and extends upwardly to switch lever 48 ou an electric control switch 49. This switch controls the circuit of electric driving motor 50, as will hereinafter more fully appear.

The fuel charging mechanism comprises a carriage 51 slidably mounted in a casng 52 disposed beneath the coal hopper Said casing forms a passageway having discharge opening 54 at its inner end, disposed at one side of and within the fire box 13 directly over the grate 15 as clearly shown in Figures 1 and 2. The carriage 51 consists of a plurality of baille plates 55, 55 carried on the inner end thereof, and an impeller member 56 spaced horizontally from said baille plates by connecting bars 57, 57 so as to form a compartment 58 for the coal. The impeller member 56 is preferably made up of two parts 59 and 60, divided on horizontal plane. The lower part 60 is rigid with baille plates 55 and connecting bars 57 and has a part 61 adjacent its rear end, having threaded engagement with screw shaft 62. Rotation of theV screw shaft 62 in opposite directions positively reciprocates the lower impeller portion 60, together with baffle plates 55 and connecting bars 57, for feeding the coal in compartment 58 to the lire, and to withdraw said carriage again to its rearmost position for a new charge of coal. A

The upper portion 59 of the impeller member 56 is yieldably mounted on the lower member 60 so that excessive pressure on the front face of member 59, as for instance, by the wedging of coal between said impeller member and the front lower margin 63a of passage 63 from the superimposed coal hopper 35, will permit uninterrupted operation of the charging carriage. In the form shown the yieldable means comprises a series of balls 65, 65 carried by the upper member 59, and adapted` to ride on corrugated upper surface 66 of the lower impeller member (El) under tension of springs 67, 67. The tension of springs 67, 67 is adjusted so that uppeil impeller member 59 will be carried with lower member 6() under ordinary operating conditions, but when unusual obstructions are met with, such as the lodgment and jamming of a piece of coal in the passageway 63 communicating from the hopper as described, the lower impeller member 60 forming the main part of the carriage is permitted to slide longitudinally relative to the upper member f 59, and thus deliver at least a partial charge of'coal to the lire. During thereturn move'- ment of the parts, however, the normal superimposed relation of impeller parts 59 and 60 will be restored and the obstruction will i usually be removed with the next charge of 'l also provide automatic spreading means for the coal, herein consisting of a forked arm 75 pivotally mounted on support 76 carried on the discharge end of the carriage 51. Said support 76 extends upwardly so that the pivotal axis 77 of spreader arm 75 is disposed above the upper margin of discharge passage 54. A detent 7 8 is disposed adj acent-the pivotal axis of said arm and adapted to en age a projection 79, forming an extension o the upper margin of discharge opening 54 (see Fig. 1). The arrangment is such that when the carriage is in fully retracted position as shown in Figures 1 and 2, the spreader arm 75 will be raised and maintained in substantially horizontal position above the lire by the engagement of detent 78 and projection 79. f

As soon as the carriage is moving outwardly, however, the spreader arm is permitted to fall by gravity into a substantially vertical position, as indicated in dotted 'lines in Figure 2. ln this position said arm engages the uppermost layers of coal and serves to .spread the iire horiaontally, as will hereinafter be more fully described.

As a part of the controlling means for the f ."j charging carriage, lprovide a pin 80 connected at one side of the lower impeller member 60 and extending laterally through slot 81, formed in casing 52, as is best shown in Figure 5. A. cooking lever 82 is pivotally mounted on pin 80 outside oiL the casing 52 and normally extends in a rearward position, riding on the pin 46 carried by lever 33. rlhe lever 82 is provided with a detent 84 which, under certain conditions, is adapted te engage the pin 46 and to carry it into locking osition with respect to detent 45 carried by ever 41 A chain 85 connected with an upwardly extending part 86 on lever 82 is adaptedto trip and disengage said lever from pin 46 when the carriage is in vfully retracted position, as will hereinafter be described. A projection 83 is provided on the upper side of level` 82 to automatically turn o" the main power switch 49, as will aise be more fully described. The outer end ci pin 80 has a horizontally disposed rod 90 passin therethrough. This rod is connected with t e operating lever 910.' of an electric reversing switch 91 and is provided with two stops 92 and 93 at opposite ends thereof which are engageable by pin 80 at both forward or return limits of reciprocal movement of the carriage as to automatically reverse the direction of current in electric motor 50 at both, and thus produce corresponding reversible movements of said carriage.

rlhe controllin power switch 49 1s best shown in Figure 8,

and includes a plunger 94engageable by projection 83 on lever 82, vertically movable in a support' 94a and having a 'clevis 95 slidably mounted on its upper end. A coil spring 95a is connected between said clevis and a collar 96 hxed on said plunger. The clevis is pivotally connected to'a lever 97 connected to switch 49 on the side opposite lever 48. Lever 48 is provided with a pin 48a movable vertically in slot 47a; on the upper end of switch operating rod 47.

The electrical system for controlling the motor 50 includesgnain power switch 49 andd reversing switch 91, both of the ordinary snap or quick acting type well known in thel art, and their circuit connections are shown diagrammatically in Fig. 13. From this figure .it will be seen that when the main switch lever 97 is raised the switch contact mechanism for the main- 117 is open, cutting oii all power to the motor Y from the main supply line 115. When con' tact 117 is closed the circuit may be established through the motor armature 119 in forward or reverse direction, depending upon the osition of reversing switch lever 91a whic controls Contact segments 121 and 122 of reversing switch 91. ln the position of the l switch lever 91a, shown in Fig. 13the circuit is established through conductor 116, iield winding 118, and conductor 120, and from thence through se ent 132, conductor 123. armature 119, con uctor 124, segment 121 to main line 125. When the switch lever 91a is shifted in a counter-clockwise direction, however, as shown in Fig. 10, the current through the armature 119 is reversed so as to reverse the direction of rotation of the motor. The circuit is then established from conductor 120 through segment 121, conductor 124, armature 119, conductor 123, segment 122 and thence to main line 125. j

lhe cycles of operation of the various controlling devices above'described may be de scribed in connection with Figs. 1, and `8 to 12, both inclusive, as follows:

When the weight of the coal sustained on grate 15 has been suihciengtlv reduced, owing to combustion, so as to cause unbalancing of Ilever 41 releases detent 45 from pin 46 as shown in Fig. 8, whereupon tension of spring 36 causes the rocking members 27, 27 in grate 15 to be moved upwardly above the surface of said grate,as shown in Fig. 9 and agitate the ashes thereon, and cause the same t0 fall through lthe grate into the ashpit. At the saine time, these rocking members '27, 27 serve to break up any clinkers that might have formed adjacent the grate.

Simultaneously with the tripping of. lever 41 the control lever 48 vof elec-tric power switch 49 will be closed by upward movement of operating rod 47 as shown in dotted lines in Figs. 8 and 9.. The spring 95a on plunger 94 is sufficientlyv light to be readily overcome and compressed by movement of the grate balancing system in case said plunger engages projection 83 on lever 82. lThis starts the motor 50 so as to ,rotate screw shaft 62 md cause the carriage 51 to'be moved inwardly with its charge of coal contained in the compartment 58. The pin 8O and lever 82 are carried with the carriage during its movement as shown 'in Fig. 9, it being noted that the chain 85 will be slaclrened as soon as the inward movement of the carriage is begun to permit the lever 82 to fall by gravity upon pin 46 carried by lever 33. lit will be understood that the latter lever with its pin will be 1n released position and swung to a position toward the furnace. The initial movement of the carriage also permits the spreader arm 75 in the furnace` to drop in substantially vertical position and engage f the upper surface to spread any excess fuel toward the furthermost wall of the fire box. As soon as the bai'ie plates 55 have passed beyond the end of the discharge opening 54, the coal contained in compartment 58 is free to :lrop between and around the connecting bars 57 onto the top of the iire. ment of the carriage continues to a predetermined position where all of the coal may be discharged therefrom. rThis position is determined by the engagement. of the outer end of pin 8O at one side of the carriage with stop 93 adjacent the reverse switch lever 91a, whereupon further inward movement of said carriage moves the said lever 91a to actuate reversing switch 91, as shown in Fig. 10 which immediately causes reversal in the direction of rotation of the motor 50 and a corresponding reversalof movement of the carriage so as to retract the same. During his retractive movement of the carriage, the lever 82 is still in engagement with and resting on pin 46 carried by arm 33, and detent 84 on lever 82 thereupon engages pin 46 and carries it to a position behind detent on lever 41 so as to restore arm 33 with the rock# ing members 27 in normal position, as shown in Figure 1. After lever 82 has thus restored pin 46 behind detent 45, as described, the chain 85 becomes taut and raises lever 82 with its detent 84 out of engagement with pin 46,

The inward move-- as shown in Figure 11. Pin 80 carried by the charging carriage also engages stop 92 on rod 90 at the end of its retractive movement so as to again reverse the electric connections for the motor through switch 91.

In the event that the single charge of coal inserted in one reciprocal movement of the carriage is sufiicient to restore the equilibrium of the counterbalancing system, link 39 will be moved upwardly and rod 47 will be moved downwardly, but by reason of the slotted end 47 a of the latter, the position of switch lever 48 will not be disturbed until projection 83 on lever 82 is raised into engagement with plunger 94, and compresses spring 94a thereon as shown in full lines in Fig. 12. The pressure of said spring is suihcient to throw power switch lever 97 of switch 49 as seen in dotted lines in Fig. 12 so that the motor 50 will stop, with all of the parts now restored to their initial starting position as shown in Fig. 1. But in the event that the sin le charge is not suficient to establish equilibrium of the counterbalancing system, the rod 47 remains up, as seen in Fig. 11, and also holds up switch arm 48a (overcoming and fully compressing spring 94a), and thus maintains the electrical connections through switch 49 so that'the motor will continue to run, but in reversed direction, owing to action of the reversing switch 91, as described. A second reciprocal movement of the carriage will thus immediately follow, as well as a second shaking movement of the rocker members 27, 27 on the grate, in the same manner as before. Both the loading and shaking operations will therefore be repeated automatically until the full predetermined weight of coal is deposited on the grate, whereupon further charging will be discontinued by actuation of the main power switch 49 when the carriage next reaches its retractive limit of movement, as shown in Fig. 1. In case of emergency, the mechanism may be manually operated in either direction, by means of crank a shown in dotted lines.

The means for automatically feeding coal from storage hopper 35 to delivery passage 63 leading to the charging carriage, comprises a screw conveyor 100 mounted on Shaft 101 having sprocket 102 at its outer end, provided with ratchet connection 103 to drive the shaft 101 in one direction only. The sprocket 103 is connected to sprocket 104 on the same shaft 62 which forms the screw operating device for the charging car riage 51. By means of the ratchet connection 103, just described, the screw conveyor 100 will be operated in one direction only, preferably when the shaft 62 is operating to retract the charging carriage in unloaded condition. In this manner the conveyor can only be driven in a direction to carry the coal toward the loaded passage 63 and furthermore,

the motor is called upon to operate the con- 1S.

veyor only at times that the carriage isbeing retracted and, therefore, is under the least load. Similar mechanical means are provided for discharging the ashes in the ash-pit as shown herein. This means comprises a screw conveyor 105 having one end extending beneath the ash-pit of the furnace and the other end'passing over a storage pit 106, into which removable boxes are arranged at a point removed from the ash-pit so as to permit the ashes to be readily withdrawn from said pit. In connection with said storage pitI provide a plurality of separate containers 107, 107 arranged side by side, but removable individually. 'Ihe screw conveyor 105 is driven through sprocket 108, chain 109 and sprocket 110, provided with a ratchet connection 111 on shaft 62, which also permits driving engagement with the conveyor in one direction only, and preferably when the charging carriage is being retracted.

I claim as my invention:

1. In a stoking device, and in combination "with a fire box, a grate, shaking means for said grate, and means responsive to a drop in weight of fuel on said grate below a. pre- .)determined value for actuating said shaking means.

2. In a stoking device, and in combination with a fire box, a grate, eounterbalancing means connected with said grate, shaking means for said grate, and means controlled by said counterbalancing means for actuating said shaking means when the weight of fuel 1n said grate is reduced below a predetermined value.

3. In a stoking device, and in combination with a lire box, a grate, a reciprocably mov- 4. In a stoking device, and in combination with a fire box, a grate, a reciprocably movable fuel feeding carriage., counterbalancing means connected with said grate and responsive to a drop in weight of fuel thereon below a predetermined value, a motor operatively connected with said fuel feeding carriage, and control means for said motor responsive to a predetermined condition of said counterbalancing means for imparting a feeding movement to said carriage to discharge fuel into said lire box, and returning said carriage to its initial loading position. Y

' 5. In a stoking" device, and in combination with a fire box, a grate, a reciprocably movable fuel feeding carriage,lcounterbalancing means connectedwith sa1d grate and responsive to a drop in weight of fuel thereon below .positively actuating said shakin power connections for said motor includingV a predetermined value, a motor operatively connected with said fuel feeding carriage, and control means for said motor responsive to a predetermined condition of said counterbalancing means for imparting a feeding movement to said carriage to discharge fuel into said iire box, and returning said carriage to its initial loading position, said control means including a power switch operatively connected with said counterbalancing means, and a power reversing switch-automatically operated at the forward limit of its reciprocable movement.

6. In a stoking device, andin combination with a lire box, a grate, a reciprocably movable fuel feeding carriage, counterbalancing means connected with said grate and responsive to a drop in weight of fuel thereon below a predetermined value, a motor operatively connected with said fuel feeding carriage, and control means' for said motor responsive to a predetermined condition of said counterbalancing means for imparting a feeding movement to said carriage to discharge fuel into said fire box, and returning said carriage means including a power switch operatively connected with said counterbalancing means,

and a power reversing switch automatically operated at both forward or rearward limits of its reciprocable movement.v

' 7 In a stoking device, and in combination with a fire box, shaking means, a motor for means,

a control device, a floating grate responsive to variation in weight of fuel thereon and having operative connection with said control device for causing said shaking means to be actuated in a predetermined position of elevation of said grate.

8. In a stoking device, and in combination with a lire box, shaking means, a motor for positively actuating said shaking means, power connections for said motor including a control device, a floating grate responsive to variation in weight of fuel thereon and having operative connection with said control device for causin said shaking means to be actuated in a pre etermined position of elevation of said gra-te, and means for automatically shutting olfsaid motor when the grate has been restored to a predetermined position of depression.

Signed at Chicago, Illinois this 30th day of April, 1927.

FREDERICK W. VUDOZ. 

